In recent years, as global warming and soaring of oil price have become problems at a global scale, transition from fossil resources to biological resources is being hurried. Meanwhile, on the order of 10,000,000 tons per year of prior art carbon microparticles, of which carbon black is a representative, are manufactured globally as tire reinforcing agents or the like, and these are conventionally manufactured by thermal decomposition of fossil resources such as oil and such at high temperatures of on the order of 1400° C.
Here, thermal decomposition of a spherical organic macromolecule containing lignin as shown in Patent Reference 1, grinding of a thermosetting resin carbon as shown in Patent Reference 2, thermal decomposition of a thermoplastic resin microparticles having activated charcoal powder attached on the surface as shown in Patent Reference 3, deposition of non-graphite structure hollow micro-carbon vaporized by thermal plasma as shown in Patent Reference 4, carbonization of microparticular thermosetting resin prepared by suspension polymerization as shown in Patent Reference 5, grinding of a carbon material in a solvent as shown in Patent Reference 6, laser illumination of a hydrocarbon compound particle as shown in Patent Reference 7, heat treatment of specially shaped carbon black at 2000° C. or higher as shown in Patent Reference 8, thermal decomposition of a synthetic resin by arc-discharge as shown in Patent Reference 9, spray pyrolysis of carbohydrates from biomass acid decomposition products as shown in Patent Reference 10, preparation by a piezo-vibrating nebulizer granulating apparatus with a thermosetting resin as a raw material as shown in Patent Reference 11, and the like, exist as other preparation methods for carbon microparticles. Furthermore, Non-Patent References 1 to 4 are reported as scientific articles related to hollow carbon microparticles.    [Patent Reference 1] Japanese Patent Application Laid-open No. H01-207719    [Patent Reference 2] Japanese Patent Application Laid-open No. H03-164416    [Patent Reference 3] Japanese Patent Application Laid-open No. H07-187849    [Patent Reference 4] Japanese Patent Application Laid-open No. H07-267618    [Patent Reference 5] Japanese Patent Application Laid-open No. 2001-220114    [Patent Reference 6] Japanese Patent Application Laid-open No. 2002-241116    [Patent Reference 7] Japanese Patent Application Laid-open No. 2004-526652    [Patent Reference 8] Japanese Patent Application Laid-open No. 2005-281065    [Patent Reference 9] Japanese Patent Application Laid-open No. 2005-53745    [Patent Reference 10] Japanese Patent Application Laid-open No. 2005-289666    [Patent Reference 11] Japanese Patent Application Laid-open No. 2006-75708    [Non-patent Reference 1] Journal of Colloid and Interface Science, Vol. 177, 325-328 (1996)    [Non-patent Reference 2] Advanced Materials, Vol. 14, 1390-1393 (2002)    [Non-patent Reference 3] Chemistry of Materials, Vol. 15, 2109-2111 (2003)    [Non-patent Reference 4] Microporous and Mesoporous Materials, Vol. 63, 1-9 (2003)
However, no preparation technique for carbon microparticle has been established from raw materials having lignin as a main constituent. In Patent Reference 1, lignin is cited as no more than an example of raw materials for a spacer between facing substrates in a liquid crystal display device, and in order to conform to this application, it suffices that the microparticles are spherical and the particle diameter is on the order of few μm to tens of μm. However, in cases such as when the microparticles are used as filling materials, adsorption materials and the like, the characteristics of the microparticles needed depending on the application are different. In particular, many cases require light weight, high strength, high specific surface area and the like, and the establishment of a technique for preparing a carbon microparticle provided with the desired characteristics is much expected in the present technical field. As lignin is present in large quantities in nature, particularly in wood, if preparing carbon microparticles becomes possible from raw materials containing lignin, it will result in a large contribution in the transition from fossil resources to biological resources. Moreover, biomasses containing lignin such as pulp waste liquid and waste wood, which are discarded from pulp manufacturing processes, and waste from agricultural products, are discarded in large amounts, with their treatment requiring large costs and being also technically difficult.